Thermal circuit controller



Sept. 21 1926.y

J. GRIGAS THERMAL CIRCUIT CONTROLLER Filed July 8, 1925 2 Sheets-Sheet 1 a@ M W@ Sept. 21 1926.

1,600,760 J. GRlGAs THERMAL CIRCUIT CONTROLLER Filed July 8 1925 2 Sheets-Sheet 2 bals PatenteLSept. 21, l1926. l

UNITED STA Tiss PATENT oFFlca.

JOSEPH GBIGAS, OF' SCHENANDOAH, PEN N SYLYAN IA.

, A'.'IEHEBIIAJL CIRCUIT CNTRGLLER.

Application led .Tuly` 8,

' static member, or by varying the eiectof the movement through a leverage system or equivalent mechanical arrangement.

'Bhe present invention marks a departure from this type of control, andhas, as its. object, the provision of regulating means in which the extent of movement of the thermostatic element to interrupt the circuit will remain constant, while means is provided for ,regulating the action of the thermostatic element under temperature variations. The invention comprises two complementary contacts, one of which is movable by the thermostatic element, `and associating with the thermostatic element means which will be effective to regulate the responsiveness of the element to tempervature variations. This is effected, preferably, by creating a yielding opposition to the movement of the thermostatic element under temperature increase, and more, particularly, by tensioning the thermostatic element itself, which is in the form of a spring bar adapted to be readily tensioned.

In the preferred construction, the Contact, which is movable by thermostatic element, is carried-by said element, and in order to maintain the distance between said contacts constant, the complementary contact is movable with the thermostatically operable contact as the position of the latter is changed when the thermostatic `element is tensioned. Another feature of the invention consists in employing the second contact, or vthe one which is not moved by the thermostatic element to tension the thermostatic element.

The above and other objects and features of the invention will become clearer as the description proceeds in connection with the accompanying drawings, wherein there is by means of nuts 13 upon the studs.

1925, serial $32,255. K

bodi'ment ofthe invention.

In the drawings f Figure 1 is a vertical section of a sadiron with the invention embodiedtherein.

Figure 2 isa top lan view with` the cover and handle remove Figure 3 is a vertical section on the line '3--3 of Figure 1.

Figure 4 is a detail sectional view showing more clearly the construction of the arrangement of the contact` which is movable to tension the ,thermostatic element.

shown, for purposes of explanation, one em- `Figure 5 is a perspectives showing the e movable contact and coacting parts separatedl from the remainder of the device, and Figure 6 is a large, detail View showing the dial and adjusting mechanism.

eferring to the drawings for a more detailed description, 10 indicates the` base of an electric iron carrying studs 11, 11 projecting upwardly through a weighting element or plate l2, which is secured to the base The studs 11 serve to clamp between the plate 12 and the base, the heating element which may l be of any usual form, such as a flat coil 14- disposed between mica strips 15, 16 by which it is insulated from the base and plate 12.

One end 19 of the resistance coil is connected to a stationary terminal 20 and the other end is connected,by means of an upwardly bowed extension 21, with a contact 22 carried by a thermostatic element 23, which, inthe present instance, is in the form of a bar formed of different materials or metals 24, 25, having different coeihcients of` expansion. At one end, the bar is clamped upon'the plate 12 by means of a, Screw 26, and the other end carries the contact 22 which is suitably insulated rornthe bar or thermostatic element.

The thermostatic element is preferably formed of spring metals, and is arranged so that the contact 22 may cooperate with Sil with a slot 33 betiveen which fit studs 34; carried by a cover 35, the studs serving to receive the terminal plug of va lead-in or connecting Wire for the iron. IThe cover may be secured in position by means of the studs 1l, ll which project through openings therein and carry nuts 37 to secure the cover in position.

rlhe Contact 27 is movably mounted by means of the collar 30 so that it may serve as the means :tor deiiecting or bending laterally the end of the element 23, and thereby tension the same. Adjustment of the contact 2T to carrv it into enffaofement With the J C D contact 22 and to tension the thermostatic bar may be eifected by means of an arm 38 extending from the flange 29 of the collar 30 and carrying an arcuate raclr 39 which meshes with a pinion Li0 upon a pin eX- tending through the cover, and operable by means of a hand Wheel 42. The pin 4:1 carries pointer 43, which engages beads or lrnobs a upon a graduated dial 45, suitably marked to indicate the temperature at which the thermostatic element will move to interrupt 'the circuit. rlhe 'knobs la engage the indicator linger 3 and will prevent movement of the collar 30, and itscontact 27 under the opposing tension lof the tliermostatic element 23, except when Vthe pin il is moved manually to vary the tension or" the thermostatic element or to interrupt the circuit.

It will be understood that the course of the current is through the terminal 20, coil 14, contacts 22 and 27 and terminals 32; terminals 2O and 32 serve to receive pins 34 carried by the cover for engagement by the terminal plug of a connecting Wire.

In the operation of the iron, or other device to which the controller is applied, the hand Wheel 42 will rst be adjusted to engage the lcontacts 22, 27, thereby completing the circuit, and also -to tension the thermostatic element 23 to the desired extent, which yvill depend upon the temperature to which itis desired to heat the iron, it being understood that the more the contact 27 is moved to lien the thermostatic element, the greater will be the tension of the latter, and, consequently, the higher will be the temperature required to cause the thermostatic element to carry the contact 22 away from the contact 27 and interrupt the circuit. The graduations upon the dial adjacent the hand wheel Will indicate to the operator the temperature selected for operation of the thermostatic element to edect breaking of the circuit, and the beads or knobs 44 in the dial will retain the hand Wheel and pointer 43 in any selected position in opposition to the tension of the thermostatic bar. Vhenever the temperature of the iron is raised beyond the predetermined degree selected, the thermostatic bar will separate the con tacts 22 and 27 and maintain them separated until the temperature falls below the selected degree when the thermostat will automatically carry the contact 22 back into engagement With the contact 27.

Obviously, numerous modifications may be made in the structure illustrated and described Without departing from the invention, which is set forth "in the foregoing specication and in the drawings in detail simply for purposes of explanation, and in no sense to define the invention, the same beino' dened by the following claims. claim:

ln combination with a heating element, thermostatic means for controlling the heat of said element comprising a thermostatic strip xedly anchored and having a free end remote from said anchorage, a contact element carried by said strip adjacent said free end, a complementary contact adjustably mounted :tor movement relative to said irst mentioned contact and its thermostatic strip, and manually operable means' remote from said contacts to adjust said comple:- mentary contact, said means beingV adapted through adjustment ot said Contact to flex saidthermostatic strip and vary its. tension.

2. In combination With a heating element, thermostatic means for `controlling the heat of said element comprising a thermostatic strip lixedly anchored and having a free end remote from said anchorage, a contact element carried by said strip adjacent said free end, a complementary contact adjustably mounted for movement relative to said rst mentioned contact and its thermostatic strip, and manually operable means remote from said contacts to adjust said complementary Contact, said means being adapted through adjust-ment of said contact to flex said thermostatic strip and vary its tension, and being also adapted to move apart and together said contacts, and therebyA manually to make and break a circuit. j

3. In combination with a heating element, thermostatic means for controlling the heat of said element comprising a thermostatic strip `ixedly anchored and having a free end remote from said anchorage,.-a Contact element carried by s'aid strip adjacent said free end, a complementary contact adjustably mounted for movement relative to said first mentioned contact and'its thcrmostatic strip, and manually operable means remote from said contacts to adjust said `complementary conta/ct, said means being adapted throu h adjustment of said contact to flex said t ermostatic strip and vary its tension and comprising a rotatable shaft, means for supporting said complementary contact for movement, a p ivotally movable arm con- 4. In combination with a heating element, thermostatic means for controlling the heat of said element comprising a thermostatic,

strip ixedly anchored and having a Jfree end remotev from said anchorage, a contact element carried by said strip adjacent said free end, a complementary Contact adjustably mounted for movement relative to said first mentioned Contact and its thermostatic strip, and manually operable means remote from said contacts ,to adjust said complementary contact, said means being adapted through adjustment o said contact to flex said thermostatic strip and vary its tension and comprising a rotatable shaft, means for supporting said complementary contact for -free sliding movement, a pivotally movable arm connected to said complementary contact, and rack and pinion means for moving said arm from the shaft.

5. In combination with a heating element thermostatic means for controlling the heat of said element comprising a thermostatic strip xedly anchored and having a free end remote from said anchorage, a contact element carried by said strip adjacent said free end, a complementary contact adjustably mounted for movement `'relative to said first mentioned Contact and its thermostatic strip, and manually operable means remote from said contacts to adjust said complementary contact, said means being adapted through adjustment of said contact to flex said thermostatic strip and vary its tension, and comprising a stationary terminal having a guide eye,V said complementary contact being freely slidable in said eye and making therein an electrical connection with said terminal, an arm connected with said contact but insulated therefrom, and rack and pinion means for moving said arm and thereby imparting a sliding movement to said complementary contact.

In testimony whereof I have hereunto set my hand.

JOSEPH GRIGAS. 

